<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">
        var a=12;
        var b="12";
        alert(a==b);//true 字面量的比较
        alert(a===b);//false 除了比较字面，还要比较类型
    </script>
</head>
<body>

</body>
</html>